This disclosure relates to scroll devices and more particularly to a scroll device having a pressure plate for preventing damage to the scroll device.
Scroll type devices, such as compressors, typically employ two interleaving scrolls that often, but not exclusively, employ involute vane geometries to pump, compress, expand, or pressurize fluids, such as liquids or gases, with such liquids or gases typically being introduced into the scroll type device through an inlet or input port and discharged through a discharge port. One of the interleaving scrolls is held fixed while the other scroll orbits eccentrically, without rotating, to trap and pump or compress pockets of fluid between the scrolls. Although other techniques are used for effecting suitable relative motion between the scrolls such as co-rotating the scrolls. The scroll type devices having two interleaving scrolls generally tend to be compact and operate more smoothly, quietly, and reliably than previous types of compressors.
Scroll devices have been used as compressors and expanders, and vacuum pumps for many years. In general, these devices may have a single stage of compression having a spiral involute or scroll upon a rotating plate orbits within a fixed spiral or scroll upon a stationery plate. A motor shaft turns a shaft that orbits a scroll eccentrically within a fixed scroll. The eccentric orbit forces a gas through and out of the fixed scroll thus creating a pressure in a container in communication with the fixed scroll. An expander operates with the same principle only turning the scrolls in reverse. When referring to compressors, it is understood that a vacuum pump can be substituted for compressor and that an expander can be an alternate usage when the scrolls operate in reverse from an expanding gas.
Currently, scroll devices may be semi-hermetic or hermetic scroll devices which have a fixed scroll positioned on an end of a compressor for sealing between ambient pressure and operating pressure. The scroll is machined on the inside of the scroll. The fixed scroll takes an axial pressure load from the difference between ambient pressure and internal operation pressure. This results in deflections on the spiral involute. These deflections on the fixed scroll can result in deformation of the scroll geometry machined on the inside of the scroll. The deformation of the scroll geometry can result in the involute contacting the orbiting scroll component. This can lead to failure of the scroll and should be avoided.
The present disclosure overcomes the limitations of the prior art where a need exists for preventing a deformation of the scroll geometry. It would also be advantageous to have a scroll device having a pressure plate that is capable of preventing damage to the scroll regardless of whether an interface pressure is at low operating pressure or at high operating pressure.